The general procedure for synthesizing 1,2-dichloro-3-iodobenzene from iodobenzene is as follows: in Example 6, the preparation of dichloroiodobenzene, chlorine gas was passed in a bubbling manner into a solution of iodobenzene (20.4 g; 0.1 mol) dissolved in chloroform (100 ml), while controlling the temperature of the reaction mixture to be maintained at -5 °C. After about 10 minutes, a yellow solid precipitate appeared in the reaction mixture, which was separated by filtration. Subsequently, chlorine gas was continued to be passed into the filtrate until no more yellow solid was produced. All obtained solid portions were combined and dried in air to give 25.9 g (94.2% yield) of the target product 1,2-dichloro-3-iodobenzene.
